Friday, June 20, 2008

Male Infertility: Intracytoplasmic Sperm Injection (ICSI)

Background

Male infertility accounts for the reason for the problem in approximately 40% of the 2.3 million couples experiencing infertility in the US. Traditionally, couples with severe male factor had three options: using donor sperm, adopting or electing not to have children. The plight of men with severe sperm problems having their own biological children was a strong force in the development of new approaches.

Treatment of male infertility often depends on the specific cause of the infertility and can include surgery, medical treatment and if those are not effective, microinsemination techniques. Microinsemination is laboratory assisted fertilization of an egg. Intracytoplasmic sperm injection (ICSI), a specialized form of microinsemination, was first developed by reproductive medical specialists in Belgium to help couples overcome male infertility problems associated with an inability of sperm to fertilize an egg. Since then, ICSI has been successfully used to treat many types of male infertility and is helping more couples realize their dream of having their own biological children even in the most severe cases of male infertility. Today, the technique is no longer considered experimental and is among our routine services.

The ART of Parenthood

There are several Assisted Reproductive Technologies (ART) that have been developed to assist couples in having children. Among them are: in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT), egg donation, cryopreservation with subsequent thawing and transfer of embryos, and a growing number of microscopic techniques such as ICSI and most recently, preimplantation genetic diadnosis (PGD). These microscopic procedures are the most demanding and exacting part of ART.

Male Infertility & ICSI

Fertilization of the egg by ICSI, getting one sperm into one egg, is the starting point for embryo development. For many years the only approach available for fertilizing an egg in ART procedures was to imitate what occurs in fertile couples, incubating the egg with sperm. This approach is successful in fertilizing approximately 75% of eggs in men with normal sperm parameters. Microinsemination techniques were developed to improve the likelihood of fertilization in men whose sperm parameters are markedly abnormal. Male infertility can be associated with the production of low numbers of sperm, sperm that do not “swim” properly or do not swim at all, and sperm that are abnormal in shape. Abnormally shaped sperm have reduced ability to penetrate the egg.

Non-ICSI insemination can be a difficult process in men with abnormal sperm parameters for two reasons: the sperm must first reach the egg and then penetrate the egg. They may not have adequate numbers, motility or normal morphology to have a good chance of their sperm accomplishing these two tasks. ICSI overcomes these deficiencies by injecting a single sperm into an individual egg. ICSI makes a low number of sperm, “poor sperm motility” and “poor sperm morphology” no longer barriers to couples who seek to have their own biological children.

In some men, the tubes known as the vas deferens that transfer sperm from the testis are blocked or missing through a congenital abnormality, an accident, a disease or an irreversable vasectomy. In such situations, sperm may be obtained by a surgeon from the epididymis, the site where sperm are stored through a process called percutaneous epididymal sperm aspiration (PESA). In men with other severe problems, sperm can be obtained by testicular biopsy (TESE). ICSI makes it possible to use epididymal or testicular sperm to achieve a pregnancy. There is also the situation where, for unknown reasons, a man’s sperm does not penetrate the woman’s egg, even though the number, shape and motility of the sperm all appear normal. ICSI is also appropriate treatment in these situations.

ICSI - The Technique

ICSI requires only one sperm per egg to be effective. ICSI is a simple and elegant way to transfer that sperm directly into the egg. Using a microscope, the embryologist gently draws one sperm into a pipette. The tip of the pipette is then guided into the waiting egg. The egg is held steady at the end of another glass pipette. Then with a steady and measured forward motion, the sharpened tip of the sperm-containing pipette is inserted into the egg. Reversing the process that pulled the sperm into the pipette, the embryologist now ejects the sperm into the egg. And finally, the sharpened tip of the empty pipette is removed from the egg. After picking up the sperm, the entire ICSI technique takes the embryologist less than ten minutes.

ICSI - Does it damage the egg?

ICSI procedures are routinely done successfully without damaging the egg in most cases.

This is not surprising to embryologists for several reasons. First, the egg is many times larger than the pipette that is used to penetrate its surface. Second, the human egg is encased in a tough, elastic membrane that usually doesn’t crack, shatter or crumble.

Finally and most important, Mother Nature lends a hand: the egg has the ability to rapidly repair the small hole in its membrane made by the pipette.

ICSI - Are there any side effects?

Despite widespread use and acceptance, ICSI is still a relatively new procedure. Children born as the result of ICSI are still very young and have not yet reached an age to reproduce. Genetic reproductive abnormalities in the father can be passed on to male offspring. Currently there are reports of a small increase in minor birth defects and congenital abnormalities in babies born through ICSI. This is not surprising since it is usually being performed in couples in which the man has very abnormal sperm. In addition ICSI bypasses an important natural process of sperm penetration.

Theoretically, this could permit the transfer of certain conditions that have a genetic basis. Where a genetic basis for male infertility is suspected or known, the couple may also find it helpful to speak with a genetic counselor before choosing to use ICSI, as well as have genetic testing for abnormal chromosomes or microdeletion in the male (Y) chromsome.

Credits –

This information is provided by Arthur L. Wisot, M.D., F.A.C.O.G., one of the team of outstanding fertility doctors at the Southern California fertility center, Reproductive Partners Medical Group. For more information on IVF and the many available fertility treatments please visit www.reproductivepartners.com.